6jnx

Cryo-EM structure of a Q-engaged arrested complexCryo-EM structure of a Q-engaged arrested complex

6jnx, resolution 4.08Å Show:Asymmetric Unit Biological Assembly Structural highlights 6jnx is a 11 chain structure with sequence from Bacteriophage sfi and Ecoli. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: Gene: rpoA (ECOLI), rpoB (ECOLI), rpoC (ECOLI), rpoZ (ECOLI), rpoD (ECOLI), Q (Bacteriophage SfI) Activity: DNA-directed RNA polymerase, with EC number 2.7.7.6 Experimental data: Check Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [RPOC_ECOLI] DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates.[HAMAP-Rule:MF_01322] [RPOB_ECOLI] DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates.[HAMAP-Rule:MF_01321] [RPOA_ECOLI] DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. This subunit plays an important role in subunit assembly since its dimerization is the first step in the sequential assembly of subunits to form the holoenzyme.[HAMAP-Rule:MF_00059] [RPOZ_ECOLI] Promotes RNA polymerase assembly. Latches the N- and C-terminal regions of the beta' subunit thereby facilitating its interaction with the beta and alpha subunits.[HAMAP-Rule:MF_00366] [RPOD_ECOLI] Sigma factors are initiation factors that promote the attachment of RNA polymerase to specific initiation sites and are then released. This is the primary sigma factor of this bacterium. Publication Abstract from PubMed Bacteriophage Q protein engages sigma-dependent paused RNA polymerase (RNAP) by binding to a DNA site embedded in late gene promoter and renders RNAP resistant to termination signals. Here, we report a single-particle cryo-electron microscopy (cryo-EM) structure of an intact Q-engaged arrested complex. The structure reveals key interactions responsible for sigma-dependent pause, Q engagement, and Q-mediated transcription antitermination. The structure shows that two Q protomers (Q(I) and Q(II)) bind to a direct-repeat DNA site and contact distinct elements of the RNA exit channel. Notably, Q(I) forms a narrow ring inside the RNA exit channel and renders RNAP resistant to termination signals by prohibiting RNA hairpin formation in the RNA exit channel. Because the RNA exit channel is conserved among all multisubunit RNAPs, it is likely to serve as an important contact site for regulators that modify the elongation properties of RNAP in other organisms, as well. Structural basis of Q-dependent transcription antitermination.,Shi J, Gao X, Tian T, Yu Z, Gao B, Wen A, You L, Chang S, Zhang X, Zhang Y, Feng Y Nat Commun. 2019 Jul 2;10(1):2925. doi: 10.1038/s41467-019-10958-8. PMID:31266960 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also RNA polymerase 3D structures Sigma factor 3D structures